Temporal and lateral dynamics of HIV shedding and elevated sodium in breast milk among HIV-positive mothers during the first 4 months of breast-feeding.

OBJECTIVE

To better understand the dynamics of breast milk HIV shedding and its relation to postnatal HIV transmission, we investigated the temporal and lateral relations of breast milk viral shedding and sodium concentrations in HIV-positive women.

DESIGN

This was a longitudinal cohort study in Lusaka, Zambia.

METHOD

We examined patterns of HIV shedding in breast milk over the first 4 months of breast-feeding and their correlations with postnatal HIV transmission among 138 breast-feeding mothers. Sodium concentration in breast milk was also examined in the same samples and in breast milk from 23 HIV-negative controls.

RESULTS

Higher breast milk viral load at 1 week, 1 month, and 4 months and consistent viral shedding in breast milk were significantly associated with increased risk of HIV transmission. Elevated breast milk sodium concentration (> or =13 mmol/L) at 4 months was associated with HIV transmission, low maternal CD4 cell count, and high maternal plasma viral load. Elevated sodium concentration at 1 week postpartum was common and was not associated with any of these parameters.

CONCLUSIONS

Consistent viral shedding and high breast milk viral load are strong predictors of mother-to-child HIV transmission. Although sodium concentrations later in breast-feeding correlate with breast milk viral load, increased breast milk sodium is normal in early lactation and does not predict HIV transmission.